The collection of pollen by bees
Bees require pollen for their reproduction and pollen comprises the basic larval food for bees. Most bees acquire pollen passively during flower visitation, but female bees may also collect pollen actively with the aid of various structural and behavioral
- PDF / 2,502,048 Bytes
- 13 Pages / 612.28 x 793.7 pts Page_size
- 102 Downloads / 196 Views
Abstract. Bees requ ire pollen for their reprod uction and pollen compr ises the basic larval food for bees. Mos t bees acq uire po llen passively du ring flower visitation, but fema le bees may also collect pollen actively with the aid of various structural and behavioral adaptations. Most bees have evolved adapta tions to conce ntra te pollen into discrete load s and tran sport pollen back to their nests. Th e various structura l and behavioral ada ptati ons of female bees for acquiring and tran sporting pollen are the basis of this review.
Key words: Bees, pollen co llection, pollen tr ansport , pollen groo ming, pollen removal.
Twenty-years ago I reviewed the structural, behavioral, and ph ysiological adaptations of bees for collecting pollen for a symposium held at the Missouri Botanic Garden (Th orp 1979b). The invitati on to submit a paper to this volume gives me the opportunity to revisit recent literature and updat e information in the area . Structures and behaviors for collection and tran spor t of oils from plants were treated by Rob ert s and Vallespir (1978) and Th orp (1979b), and upda ted by Neff and Simp son (198 1) and reviewed by Buchmann (1987) and the evolution of host plant specificity for pollen collection, oligolecty, was recentl y treated by Wcislo and Can e (1996) and Mull er (1996b). Th ese topics will not be treated further here . I will address the topic from the
viewpo int of the bee, recogmzmg that this co nsiders onl y part of the complex interaction s and ada ptations between flowers and their guilds of visito rs. As has been pointed out by other autho rs, flowers often develop countermeasur es to limit the amo unt of pollen that can be obtained by bees on a single visit so as to enha nce th e chances th at their pollen will reach stigmas of flowers of their species ra ther th an disappear from the system to becom e food for bee lar vae (Wes terkamp 1996, 1997a, b), especially through development of different methods of packaging or dispen sing (H arder and Thomson 1989). The morphological terminology and classification of bees used in this review follow those of Michener et a1. (1994). Among the Apoidea the apiformes (bees) and spheciformes (wasps) share a common ancestry (Michener et al. 1994). The ancestral habit of pro vision ing nests with animal food such as insects and spide rs is maintain ed in the spheciform wasps . Bees have diverged from the ir wasp-like ancesto r to use pollen as the pr imary food for their brood . Along with thi s cha nge in food habit a number of structura l and beha vior al cha nges have appeared in the bee line. Adult bees have branched bod y hair s not found among th e wasps. Even male bees are oft en hair y and accumulate con siderable pollen on their bodies while foraging for nectar. Thus they may play significant roles
212
in mess-and-soil type pollination. Although some female bees carry pollen internally in their alimentary canal s, most ha ve speci al ext ernal de vices for transporting pollen gleaned from flowers back to their brood nes
Data Loading...
